Abstract : An experimental investigation of the equilibrium characteristics of a distributed peripheral jet as found in an air cushion landing system is described. The parameters measured were pressure ratio, trunk shape, jet height, and flow rate. Test runs were made at trunk pressures of 40, 60, 80, 100, 120, and 140 psfg, and for jet heights from 0.17 to 1.0 inch. The cushion to trunk pressure ratio was found to be a function of jet height only; the jet height magnitude was only approximately 10 per cent of that predicted by momentum theories of flow. The jet height data agrees well with a modified plenum-chamber theory of flow which is proposed. The pressure ratio, jet height, and trunk shape remain constant for any vehicle height as the flow rate is varied. (Author)